'\" t
.TH "SD_BUS_ERROR_ADD_MAP" "3" "" "systemd 257.1" "sd_bus_error_add_map"
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.SH "NAME"
sd_bus_error_add_map, sd_bus_error_map, SD_BUS_ERROR_MAP, SD_BUS_ERROR_END \- Additional sd\-dbus error mappings
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.sp
.ft B
.nf
typedef struct {
        const char *name;
        int code;
        \&...
} sd_bus_error_map;
.fi
.ft
.sp
.ft B
.nf
\fBSD_BUS_ERROR_MAP(\fR\fB\fIname\fR\fR\fB, \fR\fB\fIcode\fR\fR\fB)\fR
.fi
.ft
.sp
.ft B
.nf
\fBSD_BUS_ERROR_MAP_END\fR
.fi
.ft
.HP \w'int\ sd_bus_error_add_map('u
.BI "int sd_bus_error_add_map(const\ sd_bus_error_map\ *" "map" ");"
.SH "DESCRIPTION"
.PP
The
\fBsd_bus_error_add_map()\fR
call may be used to register additional mappings for converting D\-Bus errors to Linux
\fIerrno\fR\-style errors\&. The mappings defined with this call are consulted by calls such as
\fBsd_bus_error_set\fR(3)
or
\fBsd_bus_error_get_errno\fR(3)\&. By default, a number of generic, standardized mappings are known, as documented in
\fBsd-bus-errors\fR(3)\&. Use this call to add further, application\-specific mappings\&.
.PP
The function takes a pointer to an array of
sd_bus_error_map
structures\&. A reference to the specified array is added to the lookup tables for error mappings\&. Note that the structure is not copied, and that it is hence essential that the array stays available and constant during the entire remaining runtime of the process\&.
.PP
The mapping array should be put together with a series of
\fBSD_BUS_ERROR_MAP()\fR
macro invocations that take a literal name string and a (positive)
\fIerrno\fR\-style error number\&. The last entry of the array should be an invocation of the
\fBSD_BUS_ERROR_MAP_END\fR
macro\&. The array should not be put together without use of these two macros\&.
.PP
Note that the call is idempotent: it is safe to invoke it multiple times with the parameter, which will only add the passed mapping array once\&.
.PP
Note that the memory allocated by this call is not intended to be freed during the lifetime of the process\&. It should not be freed explicitly\&.
.SH "RETURN VALUE"
.PP
\fBsd_bus_error_add_map()\fR
returns a positive value when the new array was added to the lookup tables\&. It returns zero when the same array was already added before\&. On error, a negative
\fIerrno\fR\-style error code is returned\&. See below for known error codes\&.
.SS "Errors"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EINVAL\fR
.RS 4
The specified mapping array is invalid\&.
.RE
.PP
\fB\-ENOMEM\fR
.RS 4
Memory allocation failed\&.
.RE
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
The code described here uses
\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call
\fBsetenv\fR(3)
from a parallel thread\&. It is recommended to only do calls to
\fBsetenv()\fR
from an early phase of the program when no other threads have been started\&.
.SH "HISTORY"
.PP
\fBsd_bus_error_add_map()\fR
was added in version 221\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsd-bus\fR(3), \fBsd_bus_error\fR(3), \fBsd-bus-errors\fR(3), \fBerrno\fR(3), \fBstrerror_r\fR(3)
